Intel® Integrated Performance Primitives
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px_ version runs faster than w7_/a6_ version

visual86
Beginner
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Hi,

I am running sample performance code from following Intel article

http://www.intel.com/cd/ids/developer/asmo-na/eng/192313.htm

This code calculates the average time taken by function ippsFFTFwd_RToPack_32f by calling it 100000 times.

Now, I tried forcing a single processor version using either w7_ a6_ and px_ version of function on same machine. On my suprise, px_version always runs 50% faster than w7_ or a6_ version. Can someone explain why so?

I am running it on my laptop

System Specification:
Centrino 1.6 GHz,
512 MB RAM,
Windows XP SP2,
MS Visual Studio .net
Clock throtteling OFF

-Visu
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Vladimir_Dudnik
Employee
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Hi,
something strange, could you please specify which version of IPP do you use?
Note, you can verify performance of IPP functions with performance tool which is delivered with IPP installation, take a look on IPP oolsperfsys folder where you can find performance data on different architectures as well as precompiled performance tests executables.
Regards,
Vladimir
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visual86
Beginner
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it is IPP 4.1.3.

Actually, I already checked perfsys data before posting my message. As per perfsys data, w7_/a6_ version should run faster but that appears to be not true on Centrino.

On the other hand, I tried running it on system with PIII and there a6_ version running faster than px_ version.

I tried multiple times on both setup with consistent results. On PIII, a6_ version is faster while on Centrino px_ version is faster than both w7_ and a6_ version.

Indeed strange.

-Visu
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Vladimir_Dudnik
Employee
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Visu,
thanks for informing about that issue. We will investigate possible reasons, if you can attach here simple test case (just to let us to use the same sequence of IPP calls) it would help.
Regards,
Vladimir
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visual86
Beginner
324 Views
Thanks Vladimir,

I am using exact code from following article:

http://www.intel.com/cd/ids/developer/asmo-na/eng/192313.htm?prn=Y


-Visu

Message Edited by visual86@yahoo.com on 08-26-2005 07:00 AM

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